Genetic Variation and Association Analysis of Elite Waxy Maize Inbred Lines in South Korea

This study aimed to evaluate the genetic diversity (GD) and association analysis for 100-kernel weight (100KW) and understand the population structure and genetic distance among Korean waxy maize inbred lines collected in South Korea. The average value of 100KW was 19.8 ± 4.7 g, with statistically significant differences between low and high groups based on the average value. GD analysis using 150 simple sequence repeat (SSR) loci showed an average of 3.94 alleles and 4.32 genotypes per locus. The average GD was 0.581, and the average polymorphic information content (PIC) was 0.522. Pairwise genetic similarity coefficients ranged from 0.229 to 0.893 with an average of 0.385. A distance-based unweighted pair group method with arithmetic mean (UPGMA) dendrogram showed all the inbred lines dividing into five subgroups at a genetic similarity of 35.1%. Group I consisted of 16 inbred lines, with nine low inbred lines and seven high inbred lines. Group II included 20 inbred lines, composed of 10 low and 10 high 100KW inbred lines. Groups III and V each had two high or low inbred lines, respectively. Group IV had only one high inbred line. The model-based population structure classified K = 2 and K = 4 based on delta K. Association analysis between 100KW and SSR markers identified five marker-trait associations (MTAs) involving four SSR markers. The information from this study may support opportunities for selecting inbred lines with desirable traits and for developing new waxy maize varieties in South Korea. This could enable maize breeders to improve crop yield and quality through marker-assisted selection (MAS).